Protected metallic arch



A. F. HALL Jan. 15,1935.

PROTECTED METALL IC ARCH Filed May 31. 1930 2 Sheets-Sheet l Jan. 15, 1935. A, HALL 1,987,738

PROTECTED METALLIC ARCH Filed May 51, 1930 2 Sheets-Sheet 2 //v VENT/JR.

dz: 5 7M1 Patented Jan. 15, 1935 UNITED STATES PATENT OFFICE .mo'reczren METALLIC ARCH of Delaware Application May 31, 1930,, Serial No. 458,544

8 Claims.

This invention relates to arches for use in locomoti erfurnaces and .consists in a metallic arch,

protected :by refractory material from the direct action of the furnace flame.

The arch'of alocomotive furnaceislocated over the fuel bedandissubjected to the direct action of the flameupon its lower side while the combustion space is extended around the end of the arch andover its upper surface. The result is that the arch is subjected ato-zintenserheat over its entire area upon both surfaces and in many arches, offering no opportunity for cooling, the

temperature of the arch is soon raised to a-destructive point. The present day developments are all in the direction of larger locomotives,

higher rate of combustion, higher temperatures and longer uninterrupted hauls-,-al1 of which'imposela heavier duty than-formerly upon the larch. Many attempts have been made heretofore to provide metallic locomotive arches in order to profit by the greater strengthwand economy of l spacelresulting from the-use otmeta-li rather'than refractory material. For the reasons above stated, however, metallic arches as heretofore constructed have not sheen successful but have been -melted, burned or Warped by the'intense heat of the locomotive furnace. lhaveidiscovcred-that a successful locomotivearch :may be constructed from metallic unitssupported in the form of-a partition-extending between the walls of theiurnace if the precaution :istaken to ,protect the faceof the units-fromthe-direct action-of the furnace flame. -In one aspect, accordingly, my invention consists .in :a protected :meta'llic arch comprising a partition built upof interrelated metal units, each unit l-ca-rrying upon one surf ace .a blccksor blocks :of refractory material supported in position to protect --the face of the unit.

In .'my prior application Serial No. 431434,, filedFebruary =26,'1=930,"I. havedisclosed a; metallic arcli constructed of box-shaped metal units, thus providing c. Wide--tshallow air space -,in the bodyaof the: arch :through whichua current .of "fresh airis conducted and finally dischargediintoi the combustion :space of :the furnace for-the: double purpose ofcmaintaining theitemperature ofzthearch with.- in safer-limits and orimproving the :economy'of combustion by supplying fresh oxygen wherezitzis most needed'in:the'.co1nbustion space of-the furnace. rInsanotheriaspect, my inventionconsists in providinga'an arch'ofi this construction withzaprotective .facing ofrefractory material. To thisaend, anaimportant' featurevof ither invention: consists: in

an arch of metal: unitstsoashaped and arranged "as to afford an air space and each provided with: means ,ior .detachably supporting a block of refractoryamaterial suspended :beneath it.

As 'hereinshown, the metal'unitscf my pro' tected arch are provided with downwardly- -extending connecting means for engaging the re.- fractory blocks and these connecting .meansare preferably removably and-interchangeably associated with the metalpunitsto sfacilitate replace-1 ment :in case 101? damage in long continued use. In this-way, it is'possible to replace not only; the refractory blocks of :the arch but also the connectingimeans. Joy which they are held in place all without replacement ,of the metal unit.

Anjimportantsfield ;of :useof..the protected; arch of my airlrentionzisrlin connection with locomotive furnaces equipped with thermo siphon tubes. Accordingly, inanother aspect my invention.com-. priseswayprotected "metallic ,archidesig-ned :ior use insuch'furnaces;andin suchzcase thernetalzunits 1 are characterized ,by heing. shaped to vloe'supportecl upon thezthermoasiphon tubes. V

flghave reterred'to the .protectedgmetallic arch of iinrentiomas embodied in an air-cooled arch butiI contemplatealso the application of the same principle to auvatemcooled. arch .such, f or example; as that disclosed i-in my :prior :application Serial No. 438,056, filed March22, ;1.=93 o1 and under such circumstances the :metal units. of the -,arch may he detachably combined with protected :blocks of :reiractoryvmaterial- '{Ifheseand other features :of the invention ;will be hestlunderstoodiand appreciated from the following description of a preferred embodiment thereof ,5. selected :for purposes; of illustration and shown. in: the :paccompanying drawings, in which Fig, i1': is:a .view in perspective of :the arch in position zin aifurnace. of .a locomotive, certain parts beingi'rbroken away;

-Fig.i2is:.a viewof the arch inzlongitudinal secrtion;

-Fig..:.3 is awview in perspectiveofvone unit of aawater-ecooled' arch .=equipped with a protected refractory: block Fig. 4 is a view in perspective, on an enlarged scale, oflone 'ofithelarch units shownwinrFlg. 1, the :.elements "being shown in spacedl-relation; and

Fig. this a similar view of atwowprotected units. of kanothervfor'm of arch.

Iihave showndnFigs. l and' 2,-the archof my invention-Jars adapted for use :with a locomotive oi the Lima .:type- ;equippe d :with therma -siphon tubes andiwhile itirhasa specialaadvantages when 'usedzsin. thisztypesofrlocomotivepit. isiiinno sense limited to such use but may be employed also in locomotives having no thermo siphon tubes but in which the arch is supported by arch tubes of usual construction. In this type of locomotive it is customary also to omit the back combustion wall which is used in many other types of locomotive and it will be understood that the arch of my invention is in no sense limited to use without a back wall.

The locomotive furnace partially shown in Fig. 2 includes a crown sheet 14 and a flue sheet 16 which, with the grate supporting the fuel bed 18 and the side walls 20, define the fire box of the locomotive. A pair of thermosiphon tubes 24 extend rearwardly from the flue sheet 16 and merge into a pair of parallel water-cooled partitions 26 which extend upwardly to the crown sheet 14 and open into the boiler. Arch supporting tubes 22 extend between the flue sheet 16 and the rear sheet, not shown. The thermoupwardly from the flue sheet and throughout 'their length are disposed in parallel relation.

The water-cooled partitions 26 of the thermosiphon system do not extend forwardly to the flue sheet or rearwardly to the rear sheet but terminate within the boundary of the fire box.

The arch herein shown is supported partly upon the thermosiphon tubes 24, partly on the arch tubes 22 and partly upon the side walls and extends transversely from one wall of the fire box to the other with a small allowance for clearance. The arch of Fig. 1 is an assembly of boxshaped metal units arranged in edgewise contact and forming a transverse section or partition. The three units 30 constituting the foremost transverse row in the arch is each provided with an unbroken wall at its forward side. The two outer units 30 are closed at their outer ends except for nipples 32 which constitute air inlet ports by which fresh air is admitted to the passage formed in the body of the metallic section. The three metal, units 34 constituting the second transverse row in the arch are provided with air inlet nipples 36 at each end which, it will be understood, extend outwardly through the furnace wall. The units 34 register with the units 30, having tongue and groove connection therewith at their upper and lower walls.

Between the water-cooled partitions 26 of the thermosiphon system and resting upon the tubes 24 is disposed a longitudinal row of box-like metal units 38, each of which is open at its front and rear side. The walls of each unit at their forward end are stepped inwardly to form an interlocking or slip connection with the next adjacent unit. The rearmost unit 40 of the center row is provided with a curved upwardly-directed lip which deflects air traversing the passage upwardly into the combustion space. It will be apparent that in assembling the arch one unit 38 after another may be positioned upon the tubes 24 and slipped forwardly into interlocking relation with the unit previously located in advance of it.

The metal units 42 employed in the wing sections of the arch are similar in shape to those employed in the central section of the arch although of slightly greater dimensions from side to side. They are similarly provided in their abutting edges with tongues and grooves to form interlocking joints and the lateral edge of each unit is tapered inwardly and upwardly to receive plastic sealing material between it and the wall 20. .The rearmost unit 44 in each wing section is provided with an upwardly-directed lip similar to that of the center section. Each unit 42 rests at its inner edge upon one of the thermosiphon tubes 24 and is provided in its outer edge with a pair of holes 46 arranged to receive inwardly-projecting studs 48 spot welded to the inner surface of the furnace wall 20. In Fig. l the right-hand wall 20 is shown as displaced toward the right for the purpose of showing the arch-supporting studs. There is sufiicient clearance between the studs 48 and the holes 46 to permit the outer edge of the unit to be positioned on the studs before its lower edge is lowered in place upon the thermosiphon tube 24.

The shape of the metal units 38 is best shown in Fig. 4, from which it will be apparent that the lower and outer corners of the unit are curved to fit the contour of the tubes 24 and that the side walls are tapered somewhat upwardly and inwardly to aiford clearance between the watercooled partitions 26. The units 38 are preferably made of cast iron, although other metals or alloys might be employed if preferred. The unit, however, is cast with a pair of parallel transversely-disposed slots 50 in its bottom face and these are undercut to receive the flange 52 of a clamping bar 54 which may be thus removably connected to the unit.

Associated with each metal unit 38 is a block 56 of refractory material such, for example, as fire clay, alundum or other ceramic product. The refractory block 56 corresponds substantially in outline with the metallic units 38 and is provided with a shouldered channel 58 in each edge shaped to receive one of the clamping bars 54. The inner portion of the block 56 is so proportioned as to leave a shallow space between its inner face and the under face of the metal unit 38 and this may be filled or not, as desired, with a sheet of asbestos 60. The clamping bars are slightly shorter than the width of the metal unit so that they do not interfere with its bearing upon the tubes 24. As will be apparent from an inspection of Fig. 4, the clamping bars serve to suspend the refractory blocks 56 in position immediately beneath the metal unit, so as to protect its lower face from the flame of the furnace, and in the assembled relation of the blocks the clamping bars 52 are also protected, as is apparent from Fig. 2. In the assembled arch, therefore, the metal units 38 form a substantially air-tight partition of which the entire lower face is protected by the assembled refractory blocks 56.

The wing sections of the arch shown in Fig. 1 are supported in part by the arch supporting tubes 22, although in many. cases these tubes may be dispensed with and the units carried entirely by the thermosiphon tubes and the side walls alone. In those cases where arch supporting tubes are employed, the blocks 56 of refractory material and the clamping bars 54 will not extend continuously for the full width of the unit but will be supplied in appropriate lengths to fit against opposite sides of the tubes. In all cases, moreover, the refractory blocks 56 may be made of convenient length ranging from the full width of the metal unit to a collection of assembled blocks which may be individually as narrow as 4 inches. It will be noted further that the rearmost metal units 40 which are shaped with upwardly curved flanges are also protected by curved segments 41 of refractory material. The entire metallic surface of the arch including the metallic clamping bars 54 is, therefore, protected from the direct action of the furnace flame by a substantial continuous layer or section of refractory material.

In Fig. 3, I have illustrated my invention as applied to a water-cooled arch in which the cooling tubes 62 are encased between supplementary metal units 64 and 66. One pair of units is shown as adapted to receive four parallel tubes 62 and the units are secured in place by a tongue and slot connection. The lower metal unit 66 is provided with undercut slots for the reception of two edge clamping bars 68 and a center clamping bar 70 by which a pair of refractory blocks 72 are detachably retained in place upon the lower surface of the metal unit. The blocks '72 may extend for the full length of the unit 66 or may be built up of a series of narrow blocks.

In Fig. are shown two units of a, metallic arch of modified construction employing a metal plate '74 curved at its longitudinal edges to fit upon thermo siphon tubes and provided with undercut grooves '76 on its lower face to receive clamping bars 78 which retain blocks 80 of refractory material shaped similarly to those shown in Fig. 4.

While I have described my invention as embodied in a complete arch, the individual units thereof are in themselves of novel construction and in another aspect, accordingly, my invention comprises a metal unit for a protected metallic arch shaped to be interrelated with others in forming a metallic arch section and each provided with clamping means for detachably suspending a refractory block or blocks beneath it.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A protected metallic arch for locomotive furnaces having thermo-siphon tubes, comprising a plurality of metal units supported in edgewise relation and resting upon said thermo-siphon tubes, and a block of refractory material suspended beneath each metal unit and substantially coextensive therewith in area.

2. A protected metallic arch for locomotive furnaces adapted to be exposed on both sides to combustion and comprising a hollow metal section built up of interrelated box-shaped units, and a block of refractory material removably supported by and beneath each metal unit and substantially coextensive therewith in area.

3. A protected metallic arch for locomotive furnaces adapted to be exposed on both sides to combustion and comprising a hollow metal section built up of units having spaced upper and lower sides, a refractory block disposed beneath the lower side of each unit and substantially coextensive in area therewith, and connecting means associated with each unit.

4. A protected metallic arch for locomotive furnaces adapted to be exposed on both sides to combustion and comprising a section of metal units with spaced upper and lower walls, clamping members detachably connected to the lower wall of each unit, and a refractory block of substantially the same outline as said unit removably held by said clamping members.

5. A protected metallic arch for locomotive furnaces. adapted to be exposed on both sides to combustion and comprising a section of hollow metal units assembled to form an inclined air passage extending longitudinally of the arch and each having transversely disposed clamping bars beneath it, and a refractory block substantially the same outline as said metal unit held by the clamping bars.

6. A protected metallic arch for locomotive furnaces adapted to be exposed on both sides to combustion and comprising a section of hollow units each having a metal bottom-plate with undercut grooves therein, flanged clamping bars removably received in the grooves, and refractory blocks held by the bars, each block being equal in size and disposed opposite to one of said metal bottom plates.

7. A protected metallic arch for locomotive furnaces adapted to extend between the furnace walls having a free edge, and comprising a metal section built up of interrelated units arranged edge to edge, studs projecting from the furnace walls to support the outer edges of said units, and

a protective section of refractory blocks suspended from the metal section.

8. A protected metallic arch adapted to be exposed to combustion on both faces in a locomotive furnace and comprising a plurality of metal units supported in edgewise contact between the walls of the furnace and forming an inclined substantially air-tight partition, blocks of refractory material of substantially the same area and outline as the metallic units, and connecting means for detachably securing each refractory block to a metal unit.

ARTHUR F. HALL. 

